Tisch
My mother took me to travel to Chengde, which is a mountainous area. On the way to the scenic spot, we have to go through many tunnels. My mother asked me, "Can you calculate the length of the tunnel?" I thought about it and said, "As long as we know the speed and the time of passing through the tunnel, we can find out the length of the tunnel, that is, distance = speed × time". After that, I silently looked forward to reaching the next tunnel so that I could try my way.
Walking, it suddenly became dark, "I entered the tunnel", and I began to silently count 180 times in my mind, that is, 180 seconds or so. After three minutes, it cleared up and "got out of the tunnel". At this time, I asked the driver that the speed was 75 km/h, which was 750,000 minutes.
3 minutes × 1250m/ min = 3750m.
It's really long
extreme
This evening, Jia Ruochen, Chen and Zhao and I went to Longhu Park to sell newspapers. It's time to start grouping. I am in a group with Jia Ruochen, and Chen and Zhao are in a group. Act now! Jia Ruochen and I walked along the road on the left, shouting, "TV news! TV next week! " In less than a minute, our group sold two copies, and they didn't even sell one.
Then we asked one by one. If it is male, we will call it uncle or brother, if it is female, we will call it aunt or sister. In this way, through hard work, our newspaper was sold out. But Chen and his team only sold four, so we helped them sell them together.
All the newspapers were finally sold out. Let's share the fruits of victory. We * * * wholesale 23 Handan radio and television newspapers. The wholesale price is 80 cents, and the retail price is 1 yuan. You can earn 20 cents by selling 1 newspaper, and we will sell all of them for 60 cents. Zhao sold two tickets to get 40 cents, and Chen sold five tickets to get 1 yuan. Jia Ruochen and I sold the most. a * * * sold 16. 3 yuan got 2 cents, and each of us, 0 yuan, got 65,438+6 cents. How happy I am!
My uncle took us to eat shaved ice to reward us. After eating shaved ice, we reluctantly said goodbye. However, we will go together next Thursday.
Tisso
My mother bought me a model of the Empire State Building. It took me about 50 minutes to assemble it. The model is 58cm tall. Its actual height is 448m, which is about 750 times that of the model. The Empire State Building has many of the best in the world: the building has set a record of four and a half stories per week; As many as 4,000 people participate in the construction every day, and the total workload exceeds 7 million working hours; * * * Use 60,000 tons of steel, 6,543,800,000 bricks, 800,000 kilometers of cables and wires, and 654.38+092 kilometers of pipelines; 1600km long telephone cable; 6,500 windows; 1860 step; 73 elevators were installed, and the elevator speed was as high as 427 meters per minute. The Empire State Building covers an area of 2.66 hectares. At that time, the total cost was $4 1 10,000, and the subsequent maintenance cost was $67 million.
Article 4
Up to today, we have finished a set of math review papers, and I have solved all the problems one by one. When doing review papers at school, I also found some Olympic math problems to do after class. There is a topic that I still remember very clearly-shopping in winter and winter. Suddenly a child wanted to make friends with her and asked her how old she was this year. Dongdong smiled and said, "My age plus 7, divided by 4, multiplied by 3 and subtracted by 2 is exactly 10. How old do you think I am? " Hearing this, the child couldn't answer.
As soon as I finished reading the topic, I arranged it into a formula according to the words of Dong Dong: {[(□+7)÷4]×3}-2= 10, and then regarded the operation in {} as the minuend, and used 10+2 to get the operation result in {} as 65438+. After listening to my analysis, the teacher nodded and praised me: "Yu, how clever!" "
chapter five
One day, I was doing my math homework in the classroom. Then, I met a math problem that I couldn't understand. This math problem is: Find the volume of a cuboid. This question gives me two conditions. The cross-sectional area is 30 square centimeters and the width is 6 centimeters. I think: isn't the volume of a cuboid multiplied by its width and height? Why did the topic only give us the area and width of the bottom? I haven't thought about it for a long time and I don't know how to do it. So I went to ask the math teacher. The teacher looked at the topic and told me that the cross section is the bottom area of the cuboid, and the width on the topic indicates the height of the cuboid. Now I finally understand how to find the volume of a cuboid. I learned a new knowledge. I'm so happy.
Later, when I saw such a topic, I was no longer afraid. I used the method taught by my teacher to distinguish the calculation method of cuboid volume from this kind of problem. This knowledge is really helpful to me. I used it to solve many problems that I couldn't understand. My heart is happier than anyone else, because I understand a truth: mathematics is full of mysteries, waiting for us to explore, make good use of and solve bigger problems and tests. The knowledge of mathematics is really endless, and we can't finish learning it. I hope to learn unfathomable math problems with my own efforts.
Article 6
During the break, Xiaowen, the "little doctor" in our class, said to the students, "Today, I will give you an interesting math problem. The topic is: two mothers and two daughters are walking by the river. How many people are there at least? " Xiaojun said: "This is not simple! Of course, there are two mothers and two daughters, so there should be 2+2 = 4 (people). " Xiaowen shook his head and said, "No, who has a different answer?" It suddenly occurred to me that my father had told me a similar topic and asked two fathers's two grandfathers. I said, "Let's look at the relationship between Xiao Lin and her mother. Xiao Lin is her mother's daughter, so there are 1 daughter and 1 mother here. Mom is grandma's daughter, so there are 1 daughter and 1 mother here.
On the other hand, two mothers and two daughters are together, and there are at least three people. "Everyone said," you really think. "
Article 7
The unit "observing objects" is really interesting. I didn't expect to find so much mathematical knowledge in the process of observation. Observing an object, one can't observe everything, so one should cooperate with one's study partners. When observing, we should pay attention to identify the main characteristics of the object, think about the difference between observing the same object in different positions while observing, and then communicate with our classmates. I found that a rectangle has two symmetry axes, a square has four symmetry axes, and a circle has countless symmetry axes. Mirror symmetry is more interesting. For example, the clock face in the mirror is 9:00 3:00, and 1: 00 is 1 1: 00, which is opposite to the real thing.
Jump bar
Today, the teacher wants us to be "doctors". Hey, what does the teacher want us to be doctors for? Oh, it turns out that the teacher wrote a wrong question on the blackboard the other day. Then, the teacher asked us to find out the mistakes in the formula on the blackboard. It turned out that there were some problems when ten people refused to admit it. One person borrowed one from ten people and ten people said, "I still have the original number here." Another problem is that a person has filled ten, but he hasn't scored one yet. After we corrected their mistakes, they finally got well. I hope they will become doctors instead of patients in the future.
Partial wine
The teacher taught me about centimeters and meters these days. When I learned that, I came home and saw my mother washing clothes. I saw the washing machine. I had a brainwave, took out an uncut pencil from the pencil case and measured it. The washing machine is about five pencils high, about one meter wide and three pencils wide, about 60 centimeters. Finally, I took out my cloth ruler and measured it again. It's only a few centimeters less than my estimate. I'm so happy.